Relay



July 24, 1934. d H, LARSON 1,967,942

RELAY Filed July 6, 1932 2 Sheets-Sheet l July 24, 1934.

C. H. LARSON RELAY Filed July 6, 1952 2 Sheets-Sheet 2 QN RN fizz/70507 Caz/'36 H jcwson M Mfg Patented July 24, 1934 UNITED STATES PATENT OFFICE RELAY of Illinois Application July 6, 1932, Serial No. 621,088

26 Claims.

This invention relates to switches in which the circuit is closed by a conducting liquid whose level is varied by a displacer moved upon some happening as, for example, the energizing or deenergizing of a magnet; and the principal object of the invention is to provide a delay in the operation of the switch after the happening that operates it.

' Further objects and advantages of the invention will be revealed as the disclosure proceeds and the description is read in connection with the accompanying drawings illustrating several embodiments and applications of the invention, and in which Fig. 1 is a vertical section through a back contact mercury switch relay in which the displacer is raised by an electromagnet;

Fig. 2 is a plan view of the same;

Fig. 3 is a section similar to Fig. 1 with parts of the magnet broken away, showing the displacer and the mercury in the position they assume immediately after the magnet is deenergized and during the delay in closing the switch;

Fig. 4 is a view similar to Fig. 3, showing the displacer and the mercury in the position they finally assume in closing the switch;

Fig. 5 is a view similar to Fig. 3, but illustrating a front contact mercury switch relay with the magnet deenergized, and the displacer floating on the mercury;

Fig. 6 is a similar view to Fig. 5, showing the mercury and the displacer in the positions they assume immediately after the magnet is energized and before the closing of the switch;

Fig. '7 is a similar view, showing the parts in the position they assume after the switch is closed;

Fig. 8 is a similar view showing the displacer and the mercury in the position they assume im- 40 mediately after the magnet is deenergized and.

prior to the opening of the switch;

Fig. 9 is a view similar to Fig. 5, showing a front contact mercury switch relay with the displacer made in two separable parts and in the position they assume when the magnet is deenergized and the switch is open;

Fig. 10 is a view similar to Fig. 9, showing the mercury and the two-part displacer in positions they assume immediately after the magnet is energized and before the switch is closed;

Fig. 11 is a view similar to Fig. 10, showing the same relay after the switch is closed; I Fig. 12 is a sectional view showing a fragment of a displacer illustrating a different construction;

Fig. 13 is a wiring diagram of one hook-up for a back contact relay;

Fig. 14 is a wiring diagram of one hook-up of a front contact relay, and

Fig. 15 is a fragmentary, perspective view of CO the upper portion of the displacer, the plug being omitted.

But these drawings and. the specific descriptions that follow are used to disclose and illustrate the invention, and not to define the scope of the patent. Furthermore, it will be understood that the drawings are not made exactly to scale, and that for any given switch requirement it is necessary to determine the size and relationship of the parts somewhat empirically. However, a clear understanding of the operation of the herein described switches will enable anyone skilled in the art to make switches in accordance with this invention.

In the several views 10 indicates a glass envelope in the form of a cylinder sealed off at 11, and having a thickened base 12 with lead-in conductors 13 and 14 sealed in it. The conductor 14 extends at considerable distance into the envelope, and is surrounded by a glass sleeve 15 sealed to the base 12 and serving to insulate the lead-in from the charge of mercury 16 until its level has been raised a desired amount. The conductors 13 and 14 are fitted, respectively, with electrodes 17 and 18, the former being always immersed in the mercury, and the latter making contact with it to close the circuit. The electrodes may be attached to the conductors, or

' may be continuations of them, as desired.

Freely movable within the envelope 10 is a hollow cylindrical displacer 19 which resembles the cartridge case of rifle ammunition except that each end is provided with a flange 20, recessed at 21, to permit free flow of gas or liquid. The. lower end of the displacer is wide open and in all operative positions surrounds the central electrode 18 and the insulating sleeve 15. The upper end 22 of the displacer is frusto-conical and has a minute central perforation 23. This location of the perforation, while most convenient in manufacture, may be changed at will as long as the perforation is kept above the liquid level.

This displacer is preferably made of Swedish iron, because of its high permeability and low residual magnetism, but other iron, and other magnetic metal, may be used.

Between the displacer and each end of the envelope is alight spring 36, of some relatively nonmagnetic material, such as nickel iron, to protect the envelope against shock in shipping and handling the switch. The gas fill is helium, hydrogen, or the like, depending upon the requirements of special service or personal preference.

The envelope 10 is loosely fitted within two metal sleeves 24 and 25 preferably of magnetic material, and held in position by the friction of a coil spring 26, wrapped closely about the envelope and bearing against the adjacent ends of the sleeves. Of course, the spring should be of non-magnetic material, such, for example, as phosphor bronze.

The sleeves 24 and 25 are clamped by clips 2'7 and 28 to a yoke 29, made of many soft iron sheets 30, held together by bolts 31 and 32.

A solenoid 33 is wound about a spool 34, telescoping with the sleeves 24, 25, between the a of the yoke 29.

In Fig. 13 the back contact relay illustrated in Figs. 1 to 4 is shown'connected in a circuit designed to light a telltale lamp 35, when the circuit through the solenoid 33 is opened, or falls below a predetermined standard.

Operation of the back contact relay By referring to Fig. 1 it will be seen that the coil 33 is energized and that the displacer 19 has assumed a raised position, closing the gap between the sleeves 24 and 25, and the mercury level has dropped below the top of the insulating sleeve 15, thereby opening the auxiliary circuit through the telltale lamp 35 (Fig. 13).

When the solenoid 33 is deenergized, the displacer immediately drops to the position shown in Fig. 3, and raises the mercury between the displacer and the walls of the envelope 10, as shown in that figure. The gas within the hollow displacer, however, is trapped and escapes slowly through the narrow opening 23. As a result the mercury level between the inner wall of the displacer and the outer wall of the insulating sleeve 15 is first lowered and then held below the top of the latter for a period depending upon the relative proportion of the parts, after which it assumes the position shown in Fig. 4, and the circuit through the telltale lamp is closed.

Operation of the front contact relay The front contact relay shown in Figs. 5, 6, 7 and 8 is very similar to the back contact relay shown in Figs. 1 to 4, theprincipal difference being in the arrangement of the air gap in the magnetic circuit with respect to the displacer and the mercury level. In the front contact relay a relatively long sleeve 37 replaces the short sleeve 24, and the relatively short sleeve 38 replaces the long sleeve 25 of the back contact relay. As a result, when connected as shown in Fig. 14, energizing the solenoid 33 will move the displacer from the floating position shown in Fig. 5 to the position shown in Fig. 6, forcing the mercury to rise between the displacer and the wall of the envelope 10 until the gas can leak through the narrow opening 23, and allow the mercury to rise to the position shown in Fig. 7.

When the solenoid 33 is deenergized the displacer immediately rises to the position shown in Fig. 8, and a partial vacuum is created within the upper portion of the displacer, with the result that the mercury in the displacer assumes the position-shown in Fig. 8 until the gas can pass through the narrow opening 23 and allow the mercury to assume the position shown in Fig. 5.

It will be seen, therefore, that there is a time delay in making and in breaking the circuit of Nickel women this relay, and by suitably adjusting such factors as the height of the insulating sleeve surrounding the central electrode, the mercury fill, the size of the hole in the plunger, etc. any desired ratio of time delay may be obtained, within limits, so when making or breaking the circuit.

Modified front contact relay The modified form shown in Figs. 9, 10, and 11 is very like that shown in Figs. 5, 6, 7 and 8, except that the displacer is made in two separable parts. The lower part is a hollow cylinder 39, having little flanges 40 at its ends, similar to flanges 20, and is made of Swedish iron, or some other selected material of high magnetic permeability and low residual magnetism.

The upper part 41 of the displacer is very similar in form to the displacer 19, but has walls somewhat thinner than the lower part 39, and is made either of non-magnetic material, or of material relatively non-magnetic, as compared with the material of the lower part 39. For example, a chromium alloy containing Chromium 17% to 19% 7% t0 9% Carbon .10% to 20% Silicon under 1.00% Iron (remainder) The deenergized or open circuit position is 0 shown in Fig. 9. Upon energizing the magnet the lower part 39 of the displacer moves to the position shown in Fig. 10, but the upper part 41 floats for a period, depending upon the proportion of the parts, until the gas can escape through the opening 23 and allow the upper part to assume the position shown in Fig. 11, when the-switch closes.

In all forms of the switches shown in the drawings, mercury vapor formed by making and breaking the circuit tends to rise in the displacer and collects about the narrow opening, causing a variance in the flow of gas through it, and thereby varying the delay. A small quantity of asbestos fiber, felt, steel wool, or the like, 42, packed lightly in the displacer, will intercept the particles of vapor and preserve the normal gas flow. When asbestos is used it should be burnt to remove all extraneous matter that would otherwise contaminate the mercury.

It is obvious from the disclosure thus far that the length of the time delay when making or breaking an electrical circuit may be varied within limits by slightly altering the position of the top of the insulating sleeve 15, by increasing or reducing the size of the opening 23, or by adjusting the switch within the coil so as to effect a greater or less travel of the displacer. Other means for changing the length of time delay may, of course, be used.

By way of example, a displacer approximately 1% inches long and inches in diameter, inside dimensions, and the cylindrical opening 23 one ten thousandths of an inch in diameter, will give a delay of about ten seconds.

Making such. a small opening 23 to exact size is difficult. An alternative is shown in Fig. 12, where opening .0040" in diameter is reduced by inserting a rod .0039" in diameter. The ends of the rod 43 are bent at each side of the opening 44 to hold it, in place. Slight deforma-. tion or reduction in .the size of the rod, to vary the efiective opening can be made with greater ease and certainty than a minute hole 23 can be varied.

I claim as my invention 1. In a relay, a sealed envelope containing electrodes, a charge of mercury, a gas fill, and a displacer including a long hollow body telescoped over one of the electrodes and having a wide opening presented to the liquid and a narrow throttling opening presented to the gas whereby the efi'ect of shifting the displacer is modified by the restricted flow of the gas through the narrow p i g.

2. In a relay, a sealed envelope containing electrodes, a charge of mercury, a gas fill, and a displacer including a long hollow body having a wide opening presented to the liquid and a narrow throttling opening presented to the gas whereby the effect of shifting the displacer is modified by the restricted fiow of the gas through the narrow opening, and a vapor trap in the hollow body between the two openings to intercept mercury vapor moving toward the narrow opening.

3. In a relay, a sealed envelope containing electrodes, a charge of mercury, a gas fill, and a displacer including a long hollow body having a wide opening presented to the liquid and a narrow throttling opening presented to the gas whereby the effect of shifting the displacer is modified by the restricted fiow of the gas through the narrow opening, and means in the hollow body to intercept liquid vapor moving toward the narrow' opening.

4. In a relay, a sealed envelope containing electrodes, a charge of mercury, a gas fill and a displacer including a long hollow body having a wide opening presented to the liquid and a narrow throttling opening presented to the gas, whereby the efiect of shifting the displacer is modified by the restricted flow of the gas through the narrow opening, and burnt asbestos fiber in the hollow body to intercept liquid vapor moving toward the narrow opening.

5. In a relay, a sealed envelope containing electrodes, a charge of mercury, a gas fill and a displacer including a long hollow body having a wide opening presented to the liquid and a narrow throttling opening presented to the gas, whereby the elTect of shifting the displacer is modified by the restricted fiow of the gas through the narrow opening, one of the electrodes being within the hollow body, a lead-in for said electrode, and a sleeve surrounding the lead-in to a level above the open circuit level of the liquid.

6. In a relay, a sealed envelope containing electrodes, a charge of mercury, a gas fill and a displacer including a body of magnetic material surmounted by a hollow body of relatively non-magnetic material presenting a wide opening to the liquid and a narrow opening to the gas, whereby the closing of the circuit is delayed (after the body of magnetic material is submerged) by the restricted passage of the gas through the narrow opening.

'7. In a relay, an envelope, a lead-in projecting a considerable distance into the envelope and enclosed in an insulating sleeve, an electrode on the lead-in above the sleeve, a charge of liquid having a gravity level below the electrode, a displacer including a hollow body of magnetic material surrounding the sleeve and of insufiicient volume to raise the liquid to the electrode, the displacer also including another hollow body surmounting the first and presenting a wide opening to it and the liquid, and a narrow opening to the gas.

8. In a relay, an envelope, a lead-in projecting rounding the sleeve and of insumcient volume to raise the liquid to the electrode, the displacer also including a hollow body of relatively non-magnetic material presenting a wide open end to the first body and to the liquid, and presenting a narrow throttling opening to the gas when the wide open end is closed by the liquid.

9. In a mercury switch, a switch envelope, spaced electrodes in the envelope, a gas fill, a. quantity of mercury in the envelope adapted to be manipulated to make or break an electrical circuit through the electrodes, an inverted cup-shaped member provided with a small opening adjacent to the top for retarding the movement of mercury within the member, in at least one direction, by the gas pressure differential existing between the interior and exterior-of the member, said electrodes being arranged so that the condition of the circuit is determined by the height of the mercury within the member with respect to a fixed pain on the envelope.

10. In a mercury switch, a switch envelope, spaced electrodes in the envelope, a gas fill, a quantity of mercury in the envelope adapted to be manipulated to make or break an electrical circuit through the electrodes, a hollow body presenting a wide opening to the mercury and a small throttling opening to the gas whereby a relatively quick change in the mercury level on the exterior of the body is followed by a retarded movement of the mercury within the body due to the restricted fiow of gas through the small opening, said electrodes being arranged so that the condition of the circuit is determined by the height of the mercury within the body with respect to a fixed point on the envelope.

11. In a mercury switch, a switch envelope, spaced electrodes in the envelope, 2. gas fill, a quantity of mercury in the envelope adapted to be manipulated to make or break an electrical circuit through the electrodes, a hollow body presenting a relatively large opening to the mercury, and a relatively small opening to the gas, whereby the change in level of the mercury within the body occasioned by corresponding changes in the mercury level on the outside of the body is modified by the restricted flow of gas through the small opening, said electrodes being arranged so that the condition of the circuit is determined by the height of the mercury within the body with respect to a fixed point on the envelope.

12. In a mercury .switch, a switch envelope, spaced electrodes in the envelope, a gas fill, a quantity of mercury in the envelope adapted to be manipulated to make or break an electrical circuit through the electrodes, a displacer supported by the mercury and comprising a tubular body presenting a relatively large opening to the mercury and a relatively small opening to the gas, means for moving the displacer to change the mercury level on the outside of the displacer whereby movement of the mercury within the displacer is retarded by the restricted fiow of gas through the small opening, said electrodes being arranged so that the condition of the circuit is determined by the height of the mercury column quantity of mercury in the envelope adapted to be manipulated to make or break an electrical circuit through the electrodes, a displacer telescoped over one of the electrodes and comprising a tubular body closed at its upper end except for a small opening, means for moving the displacer to change the mercury level on the outside of the displacer, whereby movement of the mercury within the displacer is retarded by the restricted flow of gas through the small opening, the electrode within the displacer being covered with mercury only when the mercury level within the displacer is at or above a given level with respect to a fixed point on the envelope.

14. In a mercury switch, a switch envelope, spaced electrodes in the envelope, a gas fill, a quantity of mercury in the envelope adapted to be manipulated to make or break an electrical circuit through the electrodes, an inverted cupshaped member telescoped over one of the electrodes and presenting a relatively large opening to the mercury and a relatively small opening to the gas, means for changing the mercury level on the outside of the member whereby movement of the mercury within the member, in at least one direction, is retarded by the restricted flow of gas through the small opening.

15. In a mercury switch, a switch envelope, spaced electrodes in the envelope, a gas fill, a

mercury fill adapted to be manipulated to make.

or break an electrical circuit through the electrodes, and means for producing a time delay in the operation of the switch, said means including an inverted cup-shaped member telescoped over one of the electrodes and having a restricted gas passage adjacent to the top whereby the movement of mercury within the member is retarded in at least one direction by the slow pas sage of gas through the restricted opening.

16. In a mercury switch, a switch envelope, spaced electrodes in the envelope, a gas fill, a mercury fill adapted to be manipulated to make or break an electrical circuit through the electrodes, a displacer normally displacing a sufiicient quantity of mercury to bridge the electrodes, but being adapted to be raised by magnetic force to displace a lesser amount, and means including a restricted gas passage for delaying the movement of mercury away from one of the electrodes after the displacer has been raised.

1'7. In a mercury switch, a switch envelope, spaced electrodes in the envelope, a gas fill, a mercury fill adapted to be manipulated to make 'or break an electrical circuit through the electrodes, a displacer, normally displacing an insuflicient quantity of mercury to bridge the electrodes, but being adapted to be lowered by magnetic force to displace a greater amount, and means for delaying the movement of mercury toward circuit closing position, said means including a body of gas under pressure opposing the flow of mercury to circuit closing pfiition, and means for slowly relieving said pressure.

18. In a relay, '9, switch envelope, spaced electrodes in the envelope, one of which is insulated to a point substantially above its base, a charge of mercury in the envelope, a gas fill, a cupshaped member telescoped over the'said electrode and having a small opening adjacent the top, and means for changing the mercury level on the outside of the member, whereby the movement of the mercury within the member is modified by the restricted flow of gas through the small opening in the member.

19. In a relay including a coil, a mercury switch associated with the coil and comprising a switch envelope, a gas fill, a charge of mercury in theenvelope, spaced electrodes in the envelope, a displacer supported by the mercury, said displacer consisting of an armature of magnetic material surmounted by an inverted cup-shaped body of non-magnetic material having a small opening adjacent to the top whereby when the coil is energized, the armature is lowered and permits the non-magnetic body to drop by its own weight, at a rate which is independent of the strength of the energizing force, to a position in which sufiicient mercury is displaced to bridge the electrodes, the slow escape of gas through the small opening in the non-magnetic body effecting a time delay in the making of the circuit through the electrodes.

20. In a time delay relay in which the time factor is entirely independent of the energizing force, a switch envelope, spaced electrodes in the envelope, a gas fill, a mercury fill, and a two part displacer supported by the mercury and normally displacing an insufiicient quantity of mercury to bridge the electrodes, one of said parts being made of magnetic material, and the other being surmounted on the first and being made'of nonmagnetic material, and means responsive to the movements of the non-magnetic body for delaying the making of the circuit until after a predetermined time.

21. In a mercury switch, a switch envelope, a quantity of mercury therein, a pair of electrodes sealed through the envelope, and a plunger for making and breaking an electrical circuit through the electrodes, said plunger being adapted to telescope over one of the electrodes and having means for forcing mercury to a lower level with respect to said electrode while the plunger is being lowered.

22. In a mercury switch, a switch envelope, a quantity of mercury therein, a pair of electrodes sealed through the envelope, and a plunger for making and breaking an electrical circuit through the electrodes, said plunger comprising an armature of magnetic material and having means for telescoping over one of the electrodes to force mercury to a lower level with respect to said electrode when the plunger is being lowered.

23. In a mercury switch, a switch envelope, a quantity of mercury therein, a pair of electrodes sealed through the envelope, and a plunger for making and breaking an electrical circuit through the electrodes, said plunger comprising an armature of magnetic material and being equipped with means for creating a gas trap around one of the electrodes to force mercury to a lower level with respect to said electrode while the plunger is being lowered.

24. In a mercury switch relay adapted to introduce a time delay between the functioning of a control circuit and a main circuit, the combination of a coil, 9. switch envelope associated with the coil, a mercury fill, and means responsive to the coil for retarding the movement of a portion 01' the mercury to efiect a given time delay after the condition of the control circuit has been changed, said means including a time delay element adapted to form a pocket over one of the electrodes and being provided with a restricted gas passage.

25. In a mercury switch of the class described adapted to be electromagnetically controlled by a coil, the combination of a vertical switch envelope, spaced electrodes in the envelope, a mercury fill adapted to make or break an electrical circuit through the electrodes according to its level, a plunger movable within the envelope in response to the coil for changing the mercury level, and means for retarding the movement of a portion of the mercury to effect a given time delay, said means including a pocket over said electrode having a restricted gas passage.

26. In a mercury switch of the class described adapted to be electromagnetically controlled by pocket over said electrode having a a coil, the combination of a vertical switch envelope, spaced electrodes in the envelope, a mer- CARL H. LARSON. 

